Non-steady flow turbine



M. BERCHTOLD NON-STEADY FLOW TURBINE March 25, 1958 2 Sheets-Sheet 1 Filed March 2, 1954 INVENTOR. Max 3526777040 5 2 Z M M gfl\\\\\\\\\ 6 5 Z P. .4 4 I! /v w H L zm/ 4 .07

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. NON-STEADY FLOW TURBINE Filed March 2, 1954 2 sneaks-sheet z NON-STEADY FLOW TURBINE Max Berchtold, Paoli, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application March 2, 1954, Serial No. 413,610

3 Claims. (Cl. 253-66) My invention relates to non-stationary fiow turbines and is more particularly directed to a novel two-stage single rotor turbine wherein aerodynamic wave principles are used to establish difierent pressures between the stages. a

In the prior art, multiple stage steam and gas turbines from the steam or gas.

Myinvention is particularly adaptable for use in ap- J plication where two-stage units have heretofore been used. The,two-stage units of the prior art are (a) with two separate turbine wheels, and (b) with a single turbine wheel.

Inthe case of the two separate turbine wheels arrangement, expansion occurs between the first and the second wheel. This pressure drop permits the operation asa two-stage turbine. gisadvantage of requiring two rotors and complexity of esign.

.Turbines .with anoutput below 500 kw. usually have} small mass flows and, therefore, require undesirably short blades. The blade height can be increased if the rotor However, this arrangement has the have been used in order to successively extract energy level of the kinetic energy is very high in the first stage, large losses will result therein.

Inmy novel arrangement, I provide an inter-stage operationwhereby the pressure level is adjusted in be That is, the

tween stages by aerodynamic wave action. pressure will be dropped between the first and the second stage and raised between the second and the first stage.

By this arrangement, I avoid all of the disadvantages which were heretofore encountered in the single-rotor two-stage turbine which had the pressure in the vanes' substantially equal to the exhaust pressure.

With my novel arrangement, only a portion of the potential energy is converted by the first stage nozzle intokinetic energy. Almost all of this kinetic energy is then extracted in the first stage. The remaining potential energy is then converted into kinetic energy by a second stage nozzle. Thus, the pressure is successively dropped for each stage and each stage will extract almost all of the kinetic energy available in the gas.

As heretofore noted, the losses within the stage will be determined bythe level of the available kinetic energy.

. Since the first stage nozzle only converts a percentage of potential energy into kinetic energy, which will be extracted in the'first stage, the kinetic energy level is lower than in the prior arrangement thereby resulting in substantially lower losses.

.Furthermore, since the energy of the gases leaving the first stage and prior to.the entrance of the second stage is primarily potential energy, there will be substantiallyv n'o losses in the duct work connecting these two stages.

@Thatis, since the velocity of thegases will be relatively diameters are reduced which requires undesirablerota tional speeds.

In view of the disadvantages resulting from either a small or large rotor when using the two-stage. twoturbine wheel system, a single-turbine wheel two-stage system has been used in the prior art.

The most common type turbine is the so-called partially admitted Curtis turbine. Two rows of impulse blades are mounted on one wheel. Nozzles for admittancejof gas or steam are not spread out over the entire circumference. This permits larger blade heights; however it induces windage losses in the inactive turbine-segments.

Another single rotor system uses the same blades for several passes of the same gases. This single rotor system can be designed with the desirable large blade height and desirable low speed since the total area for each stage is low. However, even though the single-rotor twostage turbine has advantages over the double-rotor twostage turbine, it has many disadvantages which will now be described.

In the .singlefstage rotor, the pressure in the rotor is approximately equal to the exhaust pressure. Therefore, the full available pressure potential energy is converted into kinetic energy in the first stage nozzle. Only a portion .of this kinetic energy can be extracted in the first stage. Hence, the relatively large remaining kinetic energy which must be passed from the output of the first stage to the intake of the second stage will result in loss of energy. That is, the relatively high velocity of the gas willbe forced to flow through the sharply curved path from the first to the second intake segment thereby substantially reducing the kinetic energylevel.

--Furthermore, since all of the energy of the gas has been converted to kinetic energy inthe first stage, large losses will re su1t. That is, since the losses will be de-v low, the losses will be substantially reduced over that encountered in the priorart arrangement. Hence, the

two disadvantages above noted are overcome in my novel arrangement.

stage are reduced.

"Aerodynamic efiects or instationary flow phenomena result in the decrease of pressure in the channels as they pass between the first and second stage and an increase in the pressure as they pass between the second and first stage.

detailed description of the instationary flow phenomena is set forth in the copending application Serial No. 454,774, filed September 8, 1954, to'Max Berchtold,

' entitled Wave Engine, and assigned to the assignee of between the pressure of the second stage and the pressure termined by the level of the kinetic energy'and since the the instant invention.

A brief review. of the instationary flow. phenomena islas follows:

As the first end of the channel reaches the trailing edge of the first input nozzle of the. first stage, an expansion wave will be created. This wave will travel,

A reverse efiect occurs as the channels pass between the second and first stage. Thus, for example, when the channels reach the trailing edge of the exhaust port of the second stage, a compression wave will be created. This wave will reach the second end of the channel when the second end'reaches the trailing edge of the input nozzle of the second stage. The compression wave will increase .the pressure in the channels to a level which is of the first stage. As the channels reach the leading Paiented.,Mar. 25, 1958.

That is, thelosses within the first stage are reduced and the losses between the first and second edge of the input nozzle to'the first stage, a second compression wave will be created. This second compression wave will traverse the channel and reach the end of the channel when .the second end ofthe channel. reaches the leading edge-of the exhaust port" of the first:

stage.

The primary object of myinvention' isto provide a novel single rotor. turbine using instationary flow phe- Another object of my invention is to provide a novel non-steady flow single rotoriturbine having a first and. second stage'wherein the energyof the gases passing between the first and second stage isprirnarily potential energy. A still further object of my invention isto provide. a novel two-stage non-steady flow single rotor turbine in which instationary flowphenomena is utilized to lower the pressure of the gas betweenthe first and second stage and to increase the pressure. of the gases between the second and first stage.

Another object of my invention is to. provide a non-- steady flow turbine wherein the input nozzle to the first stage converts only a portion of the potential energy of the input gases to kinetic energy andv in which the first stage is capable of extracting. a major portion. of. the kinetic energy from the gas.

Still another object of my invention is to provide a novel two-stage turbine in which an expansion wave will. lower the pressure between the first and second stage and compression waves. will increase the pressure between thesecond'and first stage.

These and further objects of my invention will be apparent from the following description when taken in connection with the drawings, in which:

Figure .1 is a side cross sectional view of the rotor and.

the rotor illustrating the relationship of the first stage nozzle and. the second stage nozzle to the rotor.

Figure 4a. is a side cross-sectional view of an alternate arrangement of a two-stage single-rotor turbine to which my invention can be applied. a

Figure 4b is an e'nd cross-sectional view of Figure 4a illustrating the external connection between the first and second stage.

The intake gases in the duct are at a high pressure and low velocity. The duct 10 terminates in the nozzle 11 which converts the potential energy of the intake gases into kinetic energy of intermediate pressure and high velocity. The nozzle 11 will extend over a segment of the rotor which will hereinafter be referred to as the first stage. This segment extends over less than half the circumference of the rotor, as seen in Figure 3.

The rotor 16, which drives the shaft 13, has a plurality of curved channels 17 secured to the outer circumference thereof. The intermediate pressure high velocity gas in the channels 17, located in the first stage, will have a major portion of its kinetic ener y extracted and converted into shaft power for the shaft 13. The gases will subsequently leave the rotor 16 at low velocity and intermediate pressure. The duct 18 will guide the exhaust gases at intermediate pressure low velocity from the first stage to the second stage nozzle 14.

in substantially the same manner as heretofore described "in'connection with high pressure nozzle 11.

The nozzle 14 converts the remaining potential energy of the gas in the duct 18 to kinetic energy at low pressure and high velocity. As will hereinafter be more fully described, the low pressure high velocity gas can enter the rotor segment of the second stage since a lower pressure levelhas beenestablished by non-stationary flow The second stage nozzle 14 extends over'less than action.

A substantial portion of the. kinetic energy will be extracted in the second. stage. and converted to shaft power for the shaft 13. The gases will then beexhausted .to the atmosphere through the duct 19'- at low pressure between the firstand second stagewill now be described in connection with Figure 2,

Figure 2 is an instantaneous view of the conditions existing within all of the vanes 17 at any instant of' the operation.

The intake gases at high pressure and low velocity are passed through the high pressure nozzle 11, as heretofore noted. At the opening edge 25 of the nozzle 11, a compression wave front will propagate. through the channels formed by the rotor vanes. 17; Thatis, since the intermediate pressure high velocity gas emanating from the nozzle 11 impinges upon. the medium pressure gas at test within the channels, the compression wave front 30 will be created.

'As described in my copending application Serial No. 454,774, filed September 8; 1 954, to Max Berchtold, entitledWave Engine, and. assigned to the assignee of. the instant invention; the opening edge. 26 of the connecting duct 18 is positioned on the circumference of the rotor 16 so, that the compresseion wave front 30- will reach the extreme right hand edge of'the-channelwhen the. channel reaches the. opening edge 26. That is, the compressionwave front 30 reaches the opposite end. of the channel at the time the channel reaches the opening edge 26.

Thus, all of the gases in, the channels between the high pressure nozzle 11 and the exhaust of the first stagev will be at intermediate; pressure and high velocity. The transformation of the intake gases at high. pressure and low. velocity to intermediate pressure and high velocity are described in. my above mentioned copending applications, This condition of-t-he gases exists. and remains over the; entire. segment of, channels which constitute. the s i tage... r a Y The. Q os sedge 2.8; of the. noz le 1 creates a e pe sion wave front 31. which travels. to. the opposite. end of the channel. Expansion wave 31 reaches. the end. of the channel when the. channel reaches thev closing edge 27 of the duct 18. a

The closing edge 27 of the .connecting duct 18 is positioned on the. circumference of the rotor 16 so. that the expansion wave front 31 traverses the entire length of a channel by the time the right channel edge reaches closing edge 27.

The expansion. wave front 31 will transform the intermediate pressure, high velocity gases of stage one to medium pressure gas at rest. As the channels progress will expand the medium pressure stationary gases in the Hence, the interintermediate stage to lowpressure. mediate pressurev lowv velocity. gases fed into the nozzle 14 by the duct "18 will enter the second stage as low pressure high velocity gases. That is, the remaining potential energy of the exhaust gases from the first stage will be converted to kinetic energy for conversion in the second stage. That is, the kinetic energy of the gases in the second stage will now be converted to the shaft power. The gases will now leave the second stage to the exhaust duct 19 at low pressure and low velocity. d

The pressure of the gases in the rotor channels 17 is :still low and, hence, it is now necessary to provide a second inter-stage non-stationary flow action in order to reestablish the pressure necessary for the first stage operation thereby completing one cycle of the two stage single rotor turbine. This second non-stationary action is as follows.

- The closing edge 23 of the exhaust duct 19 will result in a compresesion wave 40 to thereby transform the low pressure of the gas remaining in the rotor channels to medium pressure. The closing edge 24 of the nozzle 14 is positioned on the circumference of the rotor 16 so that the compression wave front 40 traverses a channel at the time that the channel reaches the point 24. Hence, the

wave front 40 will compress all of the gases to medium pressure as illustrated pictorially in Figure 2 and all of the gases below the wave front 40 pressure and at rest.

: On continued movement of the channels, they will subsequently pass the opening edge 25 of the nozzle 11 and the cycle will be repeated in a manner heretofore describedl i i i i It will be noted that it is necessary to give the proper curvaturefltothe nozzles 11 and 14 andvto the blade 17in order to extract the proper amount .of power ,for the designed pressure drop: Q i

It will be noted that since the relative relationship of controlling corners are designed for certain speeds and temperatures, that optimum operation will be achieved under these conditions. However, the machine will be operative although with less efiiciency when operated at other speeds and temperatures. The critical relationship which exists between the edges 25-26, 2827, 2122, 23-24 is determined by the time that it takes for the wave to traverse the length of the channel and the time of arrival of the channel at the respective edge. Since both these factors will vary with temperature and the R. P. M. of the rotor, the timing of the intermediate non-stationary flow action will be altered with the variation of these two members. However, operation will not will be at' medium be impaired, within limits, even though there is some 1 variation in R. P. M. and temperature. The variation may decrease the efficiency of operation but will not impair the operation.

In a modified arrangement, illustrated in Figures 4a and 4b, the interconnecting duct between the first and second stage is situated within the circumference encompassed by the vanes of the rotor. Thus, as best seen in Figure 4b, the duct 18 is surrounded by the vanes 17. This arrangement has the advantage of providing a straight path for the gases passing between the first and second stage through the connecting duct 18. Thus, relatively little kinetic energy of the exhaust gases from the first stage will be required for the intake to the nozzle of the second stage. However, with this arrangement, it is necessary that the vane 17 be cantilevered with respect to the rotor 16 and will therefore not permit the high tip speeds which may be obtained with the radially arranged vanes, as set forth in the embodiment of Figure 1.

In the foregoing, I have described my invention only in connection with preferred embodiments thereof. Many variations and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein but only by the appending claims.

Iclaimtf l. A singlerotor non-steady flow turbine; a plurality of blades carried by said rotor; said blades curved with respect to the axis of said rotor; said blades forming channels being open at each end; a first input nozzle on" one side of said channels; a first port registering with a second end of said channels; a second input nozzle registering with said second end of said channels; a second port registering with said first end of said channels; a duct connecting said first port to said second input nozzle; said first input nozzle covering a radial portion of said channels representing the first stage of said turbine; said second input nozzle covering a radial portion of said channels representing a second stage of said turbine; said first input nozzle, said second input nozzle, said first port and said second port each having a-leading edge and a trailing edge; said edges of said ports and nozzles being positioned around the circumference of said rotor in the following sequence: said leading edge of said first input nozzle, said leading edge of said first port, said trailing edge of said first nozzle, said trailing edge of said first port, said leading edge of said second port, said leading edge of said secondnozzle, said trailing edge of said second port and said trailing edge of said second nozzle; a

first means to close ofii said first end of said channels when saidchannels pass from said trailing edge of said first nozzle to said leading edge of said second port and from said trailing edge of said second port to said leading edge of said first nozzle; a second means to close off said second end of said channels when said channels pass from said trailing edge of said first port to said leading edge 1 of said second nozzle and from said trailing edge of said second nozzleto said leading edge of said fir'st port; a first expansion wave propagated when said first end of said channels reaches said trailing edge of said'first nozzle;

said expansion wave traversing said channels and reaching the second end of said channels when said second end of said channels reaches said trailing edge of said first port; said expansion wave decreasing the pressure as said channels pass between the first stage and the area between said first and second stage; a second expansion wave propagated when said first end of said channel reaches said leading edge of said second port; said second expansion wave traversing said channel and arriving at the second end when said second end is opposite the leading edge of said second input nozzle; said second expansion wave lowering the pressure of the gases in the channels passing from the area between the first and second stage to the second stage.

2. A single rotor non-steady flow turbine; a plurality of blades carried by said rotor; said blades curved with respect to the axis of said rotor; said blades forming channels being open at each end; a first input nozzle on one side of said channels; a first port registering with a second end of said channels; a second input nozzle registering with said second end of said channels; a second port registering with said first end of said channel; a duct connecting said first port to said second input nozzle; said first input nozzle covering a radial portion of said channels representing the first stage of said turbine; said second input nozzle covering a radial portion of said chan nels representing a second stage of said turbine; said first input nozzle, said second input nozzle, said first port and said second port each having a leading edge and a trailing edge; said edges of said ports and nozzles being positioned around the circumference of said rotor in the following sequence: said leading edge of said first input nozzle, said leading edge of said first port, said trailing edge of said first nozzle, said trailing edge of said first port, said leading edge of said second port, said leading edge of said second nozzle, said trailing edge of said second port and said trailing edge of said second nozzle; a first means to close off said first end of said channels when said channels pass from said trailing edge of said 'i first nozzle to said leading edge of said second :potti and fromgsaid trailing edgeofisaidssecond port. totsaid; leading edg'eof said;first nozzle; :a;second means to. close :ofi said second; ends. of. said; channels. when; said channels; pass from saidztrailingzedge ofsaid first; port to said leadingedgeof said, second nozzle and; fromisaid trailing edge of saidsecondi'nozzle; to saidzleading edge ofv said firstport; afirst expansion wave, propagated when.- said. first end; of; said channels. reaches: said trailing edge/of said: first; noz: zle; said. first; expansion. waye-traxersingl. said channels. and reaching the seconiend of said channels whensaid second end of said channelsvreachessaid trailing edge of.

said; first; port; said. first expansion; wave; decreasing; the.

pressure. as. the. channelsipassibetween said: first stage and. the; area between said; first; and. second stage; a second: expansion wave propagatedWhtn; said. first end. of said channels. reaches. said leading edge; ofisaid; second port;

said: second expansion waye trayersing .saidichannel; andjv arriving at. the second. end when said second. end is. op-- posite; the, leading edge; of said second input nozzlexsaid.

second. expansion wavelowering the pressure ofvthe gases in the. channels: passing, from, the, area between the first and, second. stage to the second stage; a first; compression wave propagated when a channel reaches the trail? ing edge ofhsaid second portrsaid fir t; ompressionwaye traversing. aid, channel and arr ing; at. he second end thereof; when said second end reaches the railing edge of said. second input nozzle; said firstcompiiession wave increasing, the; pressure oi hegas inthechannels as they pass from said second stage to the area, between said secend s ge and s id firststage; a econd ornnr ssion wave propagated when, the channels reach the leading edge of said. first input nozzle; said second compression wave traversing said channel and arriving at said second end when saidsecond end, reaches he leading edge of said t-por said second compress on ave increasing e p essnre. othe; gases vin. he. hanne s, as; they P from the ar abetween said e nd and; first sta t s d: f t

stage; V

3., In a no bs adl-flow, tnrbinehaying: a rotor; with ra-..

dially:arrangedvanesextendingin a direction parallel. to.

the axisiofisaid rotor; andcantilevered from SaidiIOiOI; a

first input nozzle arranged alongiheportion of the outsidecircumference 'of;sai,cl vanes; said portion; covered by. said first: input nozzle; constituting; the firststage. of. said turbine; a second input. nozzle-i arranged along a portion of the inside circumferencelof said. vanes; said portion cov-.

ered bysaid second input nozzle constituting the second stage: of said: turbine; said first stage extracting a major portion of the kinetic energy of the gases therein and con-..

vetting same to rotational energy of said, rotorg'said gases passing from said first stageto-f said second input nozzle. 7 through a duct located on; the. inside. circumference of' said second nozzle; a pressure in the channels traveling between the first and second stage reduced by means of an expansion wave; the pressure in the channels passing between said second and said first stage reduced by means of a compressionwave.

References Cited in the file of this patent UNITED STATES PAT ENTS,

788,097, Ehrhart Apr. 25, 1905. 823,526 Hachenberg June 19, 1906; 1,022,683 Kienast Apr. 9, 1912 

